<International Circulation>: Triglycerides are a risk factor for coronary heart disease. What is the role of triglycerides in coronary heart disease?

    Dr Brown: Triglycerides are clearly a risk factor in that， when you measure them， the higher the triglycerides are at baseline， the greater the number of heart attacks， strokes and other cardiovascular events that occur in the population. So there is no doubt that they predict risk. The real question is how do they operate? What does an elevated triglyceride level really mean? There are several lipoproteins in the blood that we know are strongly related to vascular disease and which also change when triglycerides are elevated. So when triglycerides are up， we see less cholesterol in LDL， but there are frequently a lot more LDL particles. LDL is just a vehicle that carries cholesterol and it can carry more or it can carry less. Sometimes it has a lot of cholesterol on it and it is a big particle， but it can shrink down to a small particle. It turns out that when you have high triglycerides you have a lot of these small particles. The cholesterol level in your blood may not be terribly high but the particle number may be very high. The number of these LDL particles seems to be a risk factor related to the high triglycerides and that is the major reason why people with high triglycerides have more coronary artery disease – because they have so many small LDL particles. The other thing that happens is you make small HDL particles when you have high blood triglycerides and the number of HDL particles tends to decrease. Low HDL-cholesterol， and low numbers of HDL particles also predicts coronary events. So there are two major changes right there with high triglycerides. I believe that triglycerides themselves are not a cause of atherosclerosis but they change the cholesterol carrying particles so much that those particles become more prone to damaging arteries and lead to atherosclerosis.